Tool retainer



June 14, 1938. E, Bl LEAR ET AL, 2,120,283

TOOL RETAINER Filed Aug. 5, 1937 Tl. jg 6 5 J0 ATTORNEY Patented June14, 1938 UNITED 1 STATES 'rooL RETAINER v Earl. B. Lear and Alfred. G.Slatcher, Detroit,

Mich., assignors to Chicago Pneumatic Tool Company, New JerseyApplication August 5,

8 Claims.

This invention relates to retainers for percussive tools and moreparticularly to a drill steel retainer for a rock drill of the hammertype.

Anobject of the invention is the provision of a retainer that can beswung into and out of operative relation to thedrill steel withiminimulneffort onthe part of the operator.

Anotherobject is the provision of a retainer in which the parts that aresubject to Ywear .or `breakage are relatively inexpensive.

A feature of the invention resides in an arrangement for mounting thetrunnion bearingsin `communication with the chuck chamber so that thebearings Will be automatically lubricated. Other objects and features ofthe invention will be apparent from the following description taken inconnection with v.the accompanying drawing and appended claims.

In the .accompanying drawing, `which illustrates two embodiments of theinvention;

Fig. 1 is a front view partlyr in elevation, and partlyiin section,of arock drill embodying the invention;

Fig. 2'is a side Fig..1;

Fig. 3 is a cross section broken line 3 3 in Fig. 1;

Fig. 4 is a sectionas indicated by the arrows 4 in Fig. 1;

. Fig. 5 is a perspective view, on an venlarged scale, of one of thetrunnion washers;

Fig. v6 is a fragmentary view, similar to Fig.`1, illustrating amodication;

Fig. 7 is a plan view of the modified trunnion washer on an enlargedscale; and

Fig. 8 is a longitudinal section of the trunnion washer on the samescale as Fig. 7.

Referring to the embodiment illustrated in Figs. 1 yto 5 inclusive, adrill steel II! is provided with a collar I I engaging the lower end ofa chuck I2 mounted in a bore I3 in the front -head I4 of a rock drill.Shank I5 of the steel is of polygonal-cross section and has a slidingfit with the chuck. The upper end of the shank is adapted to receiveblows delivered by a piston (not shown).

Front head I4 Vhas a pair of aligned transverse bores I6 extendinginwardly from a pair of bosses I 'I at opposite sides of the front head.Each bore I6 provides a socket for receiving a trunnion bushing -I 8.'I'he bushinghas a hollow stem which ts the bore I6 and a flange I9which seats against a at surface on boss Il. The bushings I8 are held-intheir respective sockets by a press fit and are `adapted to be removedand replaced after they havebecome worn.` In order to prevent theelevation of the device shown in as indicated by the New York, N. Y., acorporation of 1937, `Serial No.7157,508

bushings from turning, ilanges I9 are provided with non-circular orflattened portions 20 adapted to seat on lugs 2I projecting from andintegral withv the front head. A pair-of trunnions 22 are provided with:pivot portions 23 mounted to turn in the bushings `I8.

A tool retainer member. 24 has a yoke portion 25 of ordinaryconstruction adapted'to underlie the collar'I I :on thedrill steel IIJand a pair of upstanding substantially parallel arms v26. -The arms `2li.have cylindrical extensions 21 slidingly ttingboresin the trunnions 22and have collars 28 seating against the lower ends of the trunnions. Theupper extremities of Vthe arms 26 .are provided with removable securingmeans such v as nuts 29. Compression springs k30 surround. theextensions 21 and abutagainst the nuts 29 to support the retainerin itsuppermost position with the Vcollars 28.seated on-the trunnions.V

The trunnions 22 andrretainer member- 24 are .-20

yieldinglylocked in adjusted position by means of trunnionv washers 3Isurrounding the kextensions 21 on the retainer member. 1 Eachwasher hasa flange or key'portion l32 at one-end which seats on a shoulder at theouter side of vthe associated trunnion 22..' Ak'I'hepother end of thewasher seats on one .of the camming or flat-faces 33 onthe edge of thebushing lflange I9.y IWasher 3I is held in firm` contact with thetrunnion shoulder and the bushing flange by spring 30. The bore in thewasher is slightly larger than the-diameter of extension 2-1 to permitthe vwasherto tilt as itmoves from one flat faceI 33 to another.-

In operation,v the-drill steel I0 is subjected to Vimpacts delivered bya.l vhammer piston (not shown) and, under. certainconditions,A maystrike against the yoke portion 2 5 of the yretainer member l24.3Springs 30 act as a shock absorber by per,- mitting the lretainermemberto yield in the direction of the impacts. This action minimizes wearpartsl offthe retainer. 'Iheretainer member yis normally held in theposition shownin full lines inFig. 2. When it is desired toy changeLdrill steels, the .retainer member is swung. to the broken lineposition.- Movement away from .the adjusted positionis resisteclbythe-pressure of the trunnion washer 3IV against ,the camming edge ofbushing flange I9. `As the retainer member `24 swings, it Vcarries withit the trunnions 22 and trunnion washers 3I,the latter riding over theedges separating the at faces 33 on the bushings,.l8. The key portions32 of the trunnion washers Yserve two functions: First to preventrotation of the washer about its ownaxis; and second to act as a fulcrum.on'the vfrontfheadand.prolongs.the-life of the Y for the washer as ittilts in response to the cam-` ming action of the bushing flange I9.

In accordance with usual practice, lubricating oil is supplied betweenchuck I2 and front head I4. The oil is free to pass through the bores I6to the trunnion bushings I8, thereby facilitating pivotal movement ofthe trunnions 22.

In the embodiment illustrated in Figs. 6, 7 and 8, the construction ofthe front head I4, drill steel Ill, retainer member 24 and bushings I8is the same as that of the corresponding parts in the embodiment rstdescribed. Trunnions 34 are similar to trunnions 22 but have bores oflarger diameter than the retainer member extensions 21. Trunnion washer35 has a sleeve portion 36 which is in telescoping relation to both theextensions 2l and the bore of the trunnion 34. A ilange 31 is formed atthe upper end of the sleeve and is adapted to seat on the edge ofbushing flange I9 which is provided with at or camming faces 33, shownbest in Fig. 4. Spring B holds the washer 35 in engagement with the edgeof bushing ange I9. While Fig. 6 shows the bushing and washerarrangement supporting only one arm of the retainer member 24, it willbe understood that a similar arrangement may be employed for supportingthe other arm.

The operation of the modified tool retainer is generally similar to thatof the embodiment illustrated in Figs. `1 to 5 inclusive, the principaldifference being that the trunnion 'washer 35 can move only in thedirection of the axis of the retainer member extensions 21 whereastrunnion washer 3| rocks about the fulcrum portion 32. Furtherdescription is deemed unnecessary.

It will be apparent that various changes and adaptations of theillustrative embodiment of the invention may be resorted toV withoutdeparting from the spirit of the invention or the scope of the claims.For example, one arm of the retainer member 24 may be supported as shownin Fig. 1 and the other arm supported by the modied arrangement of Fig.6. Furthermore, the front head referred to in the specification andclaims need not necessarily be in one piece but maycompriseseveral'parts carried by the cylinder either in iixed relationror so` connected relative thereto as to accomplish the results obtainedby the illustrative embodiments of the invention.

What is claimed is: i v

1. In combination with a front head and a collared working toolsupported therein, a retainer member having a yoke portion adapted tounderlie the collar and having parallel arms extending upwardlytherefrom along opposite sides of the front head, said front head havinga pair of axially aligned transverse bores, a pair of trunnions mountedfor turning` movement in said bores, said trunnions having bores inwhich the retainer member arms aremounted for sliding movement, meanslimiting sliding movement of the arms relative to the trunnions andreleasable means for locking the trunnions against pivotal movementrelative to the front head, said locking means comprising a Washersurrounding one of the arms of the retainer member, and a cam elementfixed to the front head, said washer being held in engagement with saidcam element.

2. In the combination set forth in claim 1, said washer and itsassociated trunnion having interengaging means for preventing rotationof the washer about the axis of the associated retainer member arm.

3. In combination with a front head and a collared working toolsupported therein, a retainer member having a yoke portion adapted tounderlie the collar and having parallel arms extending upwardlytherefrom along opposite sides of the front head, said front head havinga pair of axially aligned transverse bores, a pair of trunnions mountedfor turning movement in said bores, said trunnions having bores in whichthe retainer member arms are mounted for sliding movement, meanslimiting sliding movement of the arms relative to the trunnions andreleasable means for locking the trunnions against pivotal movementrelativeto the front head, said locking means comprising a washersurrounding one of the arms of the retainer member, a stationary elementcarried by the front head and having a flat portion facing said washer,and a spring holding the washer in engagement with the flat portion ofsaid element.

4. A rock drill comprising a front head and a collared drill steelsupported therein, a retainer member having a yoke portion normallyunderlying the collar and having arms extending upwardly on oppositesides of the front head, said front head having a pair of alignedtransverse bores, a pair of renewable bushings mounted in said bores andheld therein by a press fit, each bushing having a flange seated againstthe side of the front head, a pair of axially aligned trunnions mountedto turn in said bushings and removable from the front head by movementaway from each other, eachtrunnion having a bore in line with andreceiving an Varm of the retainer member, whereby said retainer membernormally prevents removal of the trunnions from the front head, saidarms having a sliding t with the trunnions, removable members secured tothe free ends of the arms, springs between said lastmentioned membersand the trunnions for resiliently supporting said arms and means yield-I ingly resisting locking movement of the trunnions and arms away fromthe normal position, said means Comprising a cam surface on theperipheral edge of one of the bushings and a washer interposed betweenassociated with the last-mentioned bushing, said washer being held incontact with said cam surface by means of said spring.

5. A rock drill comprising a front head, a collared working toolsupported therein, a retainer member for said tool having a yoke portionadapted to underlie the collar and having parallel arms extendingupwardly along opposite sides of the vfront head, said front head havinga pair of axially aligned transverse bores, a pair of renewable bushingssupported in said bores and held against movement relative to the fronthead, a pair of trunnions mounted for turning movement in said bushings,said trunnions having bores in which the retainer member arms aremounted for longitudinal movement, a spring surrounding each arm,removable means attached to the upper ends of the arms and resting onthe springs to provide a resilient support for the retainer member, awasher interposed between the lower end of one of the springs and theassociated trunnion, the associated bushing having a non-circularperipheral surface, said washer being forced 'into engagement with saidnon-circular surface to resist pivotal movement of the trunnions.

6. A rock drill according to claim 5 in which the trunnion associatedwith said washer has a shoulder at its outer end and the washer has afulcrum portion resting on said shoulder whereby the washer may tilt inopposition to spring the spring and the trunnion pressure as it iscarried over the non-circular surface.

'7. A rock drill according to claim 5 in which said washer has a sleeveportion interposed between and having a telescopic t with both thetrunnion and the arm associated therewith.

8. A rock drill comprising a front head, a co1- lared Working toolsupported therein, a retainer member for said tool having a yoke portionadapted to underlie the collar and having parallel arms extendingupwardly along opposite sides of the front head, said front head havinga pair of axially aligned transverse bores, a pair of renewable bushingssupported in said bores and held against movement relative to the fronthead, a pair of trunnions mounted for turning movement in said bushings,said trunnions having bores in which the retainer member arms aremounted for longitudinal movement, a spring surrounding each arm,removable means attached to the upper ends of the arms and resting onthe springs to provide a resilient support for the retainer member, awasher interposed between the lower end of one of the springs and theassociated trunnion, the associated bushing having an exposed portionextending beyond the side of the front head, said exposed portion havinga plurality of fiat surfaces on its periphery, said washer being held bythe spring in engagement with any one of said flat surfaces to resistpivotal movement of the trunnions away from their selected position ofadjustment.

EARL B. LEAR.

ALFRED G. SLATCHER.

